Forward scattering from solid or fluid-filled inclusion buried in multilayered elastic structures

The scattering from finite-size inclusions buried in a multilayered, elastic background structure is studied both analytically and numerically, and this information is correlated with the geometrical and elastic properties of the inclusion. The framework developed is based on a vector integral equation formalism for elastic scattering, where a Born approximation for an inhomogeneous background medium is applied to obtain a closed-form expression for the scattered field. Both compressional and shear waves are assumed to propagate inside the layers, and cross-polarization at the boundaries and multiple reflections within the layers are taken into account. The procedure was tested in cases where the Born approximation is severely put to test (100% contrast in shear modulus), and good agreement was found with results obtained independently through a finite-difference technique.